1. Technical Field
The present invention relates to an optical-type position detecting device capable of detecting the position of a target object located on one side of a translucent member and a hand apparatus and a touch panel that include the optical-type position detecting device.
2. Related Art
In robotic end effectors such as grippers, hand apparatuses and the like that are mounted on robot arms, optical-type position detecting devices that detect the position of a target object are used. The optical-type position detecting devices are configured to transmit the result of optical detection of a relative position of the target object and a hand as feedback. Generally, devices that use imaging devices have been proposed as such optical-type position detecting devices (see JP-A-2009-66678 and WO 02/18893A1). However, there are problems in that an optical-type position detecting device using an imaging device is expensive and takes a long time to process the result of the imaging operation. In addition, it is impossible to detect the gripping force at a time when the hand grips a target object from the imaged result acquired by the imaging device.
Meanwhile, a technology for optically detecting a compressive stress based on a change in the characteristics of an optical propagation medium at a time when the optical propagation medium receives a compressive stress from a target object has been proposed (JP-A-2007-71564). More specifically, the compressive stress is detected by emitting detection light toward a target object from the second face side of the optical propagation medium (translucent member) that is a side opposite to the first face side on which the target object is located and detecting the detection light reflected by the target object and transmitted to the second face side of the translucent member. According to this technology, unlike a case where an imaging device is used, the gripping force at a time when the hand grips a target object can be detected by employing a relatively simple configuration.
However, according to the technology disclosed in JP-A-2007-71564, although light reflected from a target object at a time when the target object presses the optical propagation medium is detected, the boundary state between the target object and the optical propagation medium is not stable. Thus, according to the technology disclosed in JP-A-2007-71564, there is a problem in that the burial depth (the relative position of the target object with respect to the translucent member) of the target object at a time when the target object presses the optical propagation medium (translucent member) cannot be accurately detected.